For people with high myopia or those focused on eyewear aesthetics, 1.60, 1.67, and 1.74 are the three most common high-index lens materials. The higher the refractive index, the stronger the lens bends light, allowing less material to be used for the same prescription power.
1. Core Specifications Comparison
| Attribute / Metric | 1.60 Index | 1.67 Index | 1.74 Index |
| Edge Thickness | Baseline (~20%–25% thinner than 1.50) | ~15%–20% thinner than 1.60 | ~30%–35% thinner than 1.60 (Thinnest) |
| Relative Weight | Moderate | Lightweight | Lightest (Slightly denser material, but significantly reduced volume) |
| Eye-Minimizing Effect | Mild reduction | Noticeable improvement | Minimal eye-minimizing effect (Most natural eye outline) |
| Abbe Value (Dispersion) | ~40 (Highest clarity, lowest chromatic aberration) | ~32 (Mild chromatic aberration) | ~33 (Mild chromatic aberration) |
| Recommended Prescription | -3.00D to -5.00D | -5.00D to -8.00D | -8.00D and above (High myopia) |
2. Performance Across Three Key Dimensions
Thickness (Edge Reduction)
· Myopia lenses are thin in the center and thick at the edges. As the prescription increases, the edges of 1.60 lenses become noticeably thicker.
· Upgrading to 1.67 yields a visible reduction in edge thickness, while 1.74 offers maximum thickness reduction for high prescriptions (e.g., over -8.00D), avoiding the "coke-bottle" edge appearance.
Weight & Wearing Comfort
· Although 1.74 material has a slightly higher physical density than 1.60, its overall volume is greatly reduced, making the final finished lens the lightest option.
· Lighter lenses relieve pressure on the bridge of the nose and reduce how often the glasses slide down.
Eye-Minimizing Effect & Distortion
· The shrinking effect of minus lenses depends on prescription power, base curve, and lens thickness.
· 1.74 and 1.67 lenses generally feature advanced aspheric or double aspheric designs with flatter front surfaces.
· This not only reduces the "smaller eyes" appearance from the front, but also significantly minimizes the distorted "step-off" line along the cheeks when viewed from the side.
3. Selection Recommendations & Notes
· Best Value (-3.00D to -5.00D): Choose 1.60. With a high Abbe value of 40, it offers the highest optical clarity and excellent toughness, making it ideal for rimless or semi-rimless frames.
· Balanced Performance (-5.00D to -8.00D): 1.67 is the preferred choice, striking an ideal balance between thickness control, weight, and cost.
· Ultimate Aesthetics (-8.00D+ or High Astigmatism): Opt for 1.74 to maximize visual appeal and minimize the eye-shrinking effect.
Tip: Refractive index is not the only factor determining thickness. Frame size and shape are equally crucial: choosing a smaller frame with a well-matched interpupillary distance (IPD) can make a 1.67 lens look nearly as thin at the edges as a 1.74 lens.
Post time: Sep-20-2026
